Here is what is going on behind the scenes when you get the "Download Failed" prompt: XBOX 360: GET /content/fffe07d1/manifests/0/system.manifest HTTP/1.1 User-Agent: Xbox Live Client/2.0.12583.0 Connection: Keep-alive Hostownload.xbox.com Microsoft Server: HTTP/1.1 404 Not Found Server: Apache Content-Type: text/html; charset=iso-8859-1 Content-Length: 15 Date: Tue, 19 Oct 2010 20:49:16 GMT Connection: keep-alive File not found. I've tried intercepting it, it downloads my system.manifest (from 12581) but doesn't like it, and fails with a different status code. The 360 tries 3 mirros, each 3 times. download.xbox.com download.xbox.com.edgesuite.net xbox-ecn102.vo.msecnd.net the last one is the most useful because if you browse for a directory it will give 403 (Forbidden, but exists), or 404 (Doesn't Exist). So what we need to do: Log a legit (9199, or beta tester update) packet of the update process. Determine why our updater is looking for something that isn't there. Figure out how to make it work with the above information. Sure we can just wait for the official update but what is the fun in that? And what would we learn? I have seen nothing on google about the XBL update process to apparently it is something no one ventured into.